The command in Windows for volume management is mountvol
. You should be able to use the /D option to remove the dangling mount points. For example, if you want to recover (delete and make available for another use) the drive letter F:, you would normally run (as Administrator) this command:
mountvol F: /D
I can't promise this will work for you, because I've never encountered the problem you describe. It may be that the "real" fix is just to upgrade or re-install Windows. I'm currently running Win10 x64 on this machine and have just confirmed that this doesn't happen here, but I don't remember seeing it from Win8.1 x64 either.